Contact dermatitis is a condition that makes skin red or inflamed after contact with an allergen or an irritant. Some common culprits include soap, cosmetics, fragrances, jewellery and poison ivy. The main symptom is a red rash wherever the skin came into contact with the irritant. The rash isn't contagious or life-threatening, but it can be very uncomfortable.To treat contact dermatitis successfully, you need to identify and avoid the cause of your reaction.